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First stage of reclaiming memory in executor by resetting short-term

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memory contexts.  Currently, only leaks in expressions executed as
quals or projections are handled.  Clean up some old dead cruft in
executor while at it --- unused fields in state nodes, that sort of thing.
This commit is contained in:
Tom Lane
2000-07-12 02:37:39 +00:00
parent 46fb9c29e2
commit badce86a2c
53 changed files with 1536 additions and 1584 deletions
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83
src/backend/executor/execScan.c
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@ -12,7 +12,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/executor/execScan.c,v 1.11 2000/01/26 05:56:21 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/executor/execScan.c,v 1.12 2000/07/12 02:37:01 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -30,7 +30,7 @@
* returns the next qualifying tuple in the direction specified
* in the global variable ExecDirection.
* The access method returns the next tuple and execScan() is
* responisble for checking the tuple returned against the qual-clause.
* responsible for checking the tuple returned against the qual-clause.
*
* Conditions:
* -- the "cursor" maintained by the AMI is positioned at the tuple
@ -39,59 +39,50 @@
* Initial States:
* -- the relation indicated is opened for scanning so that the
* "cursor" is positioned before the first qualifying tuple.
*
* May need to put startmmgr and endmmgr in here.
* ----------------------------------------------------------------
*/
TupleTableSlot *
ExecScan(Scan *node,
TupleTableSlot *(*accessMtd) ()) /* function returning a
* tuple */
ExecScanAccessMtd accessMtd) /* function returning a tuple */
{
CommonScanState *scanstate;
EState *estate;
List *qual;
bool isDone;
TupleTableSlot *slot;
TupleTableSlot *resultSlot;
HeapTuple newTuple;
ExprContext *econtext;
ProjectionInfo *projInfo;
/* ----------------
* initialize misc variables
* Fetch data from node
* ----------------
*/
newTuple = NULL;
slot = NULL;
estate = node->plan.state;
scanstate = node->scanstate;
/* ----------------
* get the expression context
* ----------------
*/
econtext = scanstate->cstate.cs_ExprContext;
qual = node->plan.qual;
/* ----------------
* initialize fields in ExprContext which don't change
* in the course of the scan..
* Reset per-tuple memory context to free any expression evaluation
* storage allocated in the previous tuple cycle.
* ----------------
*/
qual = node->plan.qual;
econtext->ecxt_relation = scanstate->css_currentRelation;
econtext->ecxt_relid = node->scanrelid;
ResetExprContext(econtext);
/* ----------------
* Check to see if we're still projecting out tuples from a previous
* scan tuple (because there is a function-returning-set in the
* projection expressions). If so, try to project another one.
* ----------------
*/
if (scanstate->cstate.cs_TupFromTlist)
{
projInfo = scanstate->cstate.cs_ProjInfo;
resultSlot = ExecProject(projInfo, &isDone);
if (!isDone)
return resultSlot;
/* Done with that source tuple... */
scanstate->cstate.cs_TupFromTlist = false;
}
/*
@ -100,27 +91,23 @@ ExecScan(Scan *node,
*/
for (;;)
{
slot = (TupleTableSlot *) (*accessMtd) (node);
TupleTableSlot *slot;
slot = (*accessMtd) (node);
/* ----------------
* if the slot returned by the accessMtd contains
* NULL, then it means there is nothing more to scan
* so we just return the empty slot...
*
* ... with invalid TupleDesc (not the same as in
* projInfo->pi_slot) and break upper MergeJoin node.
* New code below do what ExecProject() does. - vadim 02/26/98
* so we just return an empty slot, being careful to use
* the projection result slot so it has correct tupleDesc.
* ----------------
*/
if (TupIsNull(slot))
{
scanstate->cstate.cs_TupFromTlist = false;
resultSlot = scanstate->cstate.cs_ProjInfo->pi_slot;
return (TupleTableSlot *)
ExecStoreTuple(NULL,
resultSlot,
InvalidBuffer,
true);
return ExecStoreTuple(NULL,
scanstate->cstate.cs_ProjInfo->pi_slot,
InvalidBuffer,
true);
}
/* ----------------
@ -131,22 +118,28 @@ ExecScan(Scan *node,
/* ----------------
* check that the current tuple satisfies the qual-clause
* if our qualification succeeds then we
* if our qualification succeeds then we may
* leave the loop.
* ----------------
*/
/*
* add a check for non-nil qual here to avoid a function call to
*
* check for non-nil qual here to avoid a function call to
* ExecQual() when the qual is nil ... saves only a few cycles,
* but they add up ...
* ----------------
*/
if (!qual || ExecQual(qual, econtext, false))
break;
/* ----------------
* Tuple fails qual, so free per-tuple memory and try again.
* ----------------
*/
ResetExprContext(econtext);
}
/* ----------------
* form a projection tuple, store it in the result tuple
* Found a satisfactory scan tuple.
*
* Form a projection tuple, store it in the result tuple
* slot and return it.
* ----------------
*/